Gram staining

The identification of Escherichia coli as the unknown was concluded by a string of tests and observations such as gram-staining, shape, motility, oxidation, fermentation and citrate tests. This began with gram-staining the organism. After viewing beneath a light microscope, the unknown showed pink rods, proving to be gram-negative. The observation of motility was made by viewing the bacteria moving towards a specific direction. The next tests utilized in determining the unknown was oxidation…

It is a selective media because, it kills Gram positives but allows Gram negatives to survive. If there is growth present on the EMB media it means it is a Gram negative rod. The color of the results determine if lactose fermentation is present. If the sample is colorless then there is no lactose fermentation present. If the bacteria is purple then lactose…

viewing individual cells through a microscope at 400x power. Secondly, that the bacterium was most likely a Gram-stain-negative because it appeared to be a pink color after gram-staining. This had several implications: The experimenters now knew the bacteria’s cell wall composition, its outer membrane composition, peptidoglycan concentration, outer membrane amount, and more. Because of the gram stain results, it is evident that Bacteria F has a thin two-layer cell wall with an outer membrane…

The first procedure that needed to be done to identify the organism was a simple stain. Simple staining determines the micrograms morphology. The next procedure that had to be performed was a gram stain. Gram staining determines whether the microorganism is gram positive or gram negative. After doing these procedures it was determined that the organism was a gram positive cocci. The biochemical test performed were chosen based on this information. Principles of biochemical test:…

that I created a mixed culture for myself and was able to do a gram stain to narrow down my unknown microbes. A mixed culture contains many species that disperse into colonies after been placed in the incubator…

Using controls and tables within the Microbiology lab manual, observations were then interpreted. Through the gram staining procedure purple spherical cells were observed, and thus it is interpreted that the bacterium is not only a gram positive organism but that it is has a tetrad cell arrangement and cell morphology of a cocci. Through the oxygen tolerance test it was found that the bacterium grew predominately within…

was observed. There were multiple tiny whittish isolated colonies present, all of which showed the same growth pattern. Three colonies were chosen at random and Gram stains were performed on each (procedure for the Gram stain was used according to laboratory manual ex. 9). Each of the three Gram stains showed positive rods. After the Gram stain was determined, I began to do more research on microorganisms that had that identification and narrowing down all the possible tests to continue for…

Gram Negative Unknown Lab Report #20 BIOL 3444-008 Giang Nguyen TA: Malini Kotak 11/05/2014 Abstract The experiment is conducted in order to identify a randomly given unknown gram-negative microorganism. By comparative analysis of biochemical tests that were performed throughout the semester to find out its characteristics and determine the identification of bacterium out of four potential unknown was given. To figure out the characteristics, T-streak was performed to isolate…

down choices as tests were completed, along with a flowsheet of gram positive and negative microbes provided in Microbiology Class. To begin the process of identifying unknown microbe #7, two isolation streaks of the mystery microbe were made in order to determine whether the microbe likes to grow at 30˚C or 37˚C. It was discovered that the microbe likes to grow more at 37˚C. Next, an observation under the microscope as well as a gram stain were conducted. These tests were conducted in order…

Introduction Bacteria’s phenotype is commonly described as gram-negative or gram-positive from conducting a gram stain. A bacterium that is gram-negative tends to have cells composed of a thin peptidoglycan layer, and a gram stain of gram-negative bacteria are seen as red or pink through a microscope (Smith and Hussey, 2005). On the other hand, a bacterium that is gram-positive will have cells made of a thick peptidoglycan layer, and the gram stain of a gram negative bacteria would be seen…